2010/4/24 Matthew Fleming matthew.flem...@isilon.com:
I'm looking at kern_idle.c in stable/7 and I don't quite follow how idle
threads work. The kthread_create(9) call does not pass in a function
pointer, so what code does a processor run when there is no other
runnable thread?
In STABLE_7:
...
#ifdef SMP
SLIST_FOREACH(pc, cpuhead, pc_allcpu) {
error = kthread_create(sched_idletd, NULL, p,
RFSTOPPED | RFHIGHPID, 0, idle: cpu%d, pc-pc_cpuid);
pc-pc_idlethread = FIRST_THREAD_IN_PROC(p);
#else
error = kthread_create(sched_idletd, NULL, p,
RFSTOPPED | RFHIGHPID, 0, idle);
PCPU_SET(idlethread, FIRST_THREAD_IN_PROC(p));
#endif
...
then they rightly passes sched_idletd(). Any scheduler may define its
own version of sched_idletd().
NULL is just the argument passed that is not meaningful.
Or maybe I'm not understanding your question?
Attilio
--
Peace can only be achieved by understanding - A. Einstein
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